Radio telegraphy and telephony receiver.



e. w. PICKARD.

RADIO TELEGRAPHY AND TELEPHONY RECEIVER. APPLICATION FILED MAR. 28, I914.

1 9 1 tr; Patented May 23, 1916.

2 SHEETS-SHEET l.

G. W. PICKARD.

RADIO TELEGRAPHY AND TELEPHONY RECEiVER.

APPLICATION FILED MAR. 28. 1914.

l ,1 84,376. Patented May 23, 1916.

, I 2 SHEETSSHEET 2.

In ventor:

@REENIGEAF "WHITTIER PICKAEID, 0F AMESIBURY, MASSACHUSETTS, ASSIGNOR WIRELES$ SPECIALTY APPARATUS CQIVIPANY, OF BOSTON, MASSACHUSETTS,

CORJEORA'IION 01 NEW YORK.

RADIO TELEGRAPHY AND TELEPHONY RECEIVER.

Specification of Letters Patent.

l atented May as, ice.

Application filed March 28, 1914:. Serial No. 827,845.

To all whom it may concern:

Be it known that I, GRnnNLnnr WHIT- TIER PionAnn, a citlzen of the United States of America, and a resident of the town of Amesbury, Massachusetts, have invented certain new and useful Improvements in Radio Telegraphy and Telephony Receivers, the principles of which are set forth in the following specification and accompanying drawings, which disclose the form of the invention which I now consider to be the best of the various forms in which the principles of the invention may be embodied.

This invention relates to improvements in receiving apparatus for radio telegraphy and telephony, and consists oi-the appara' 'tus and arrangements thereof dlsclosed herein, the object of the invention being to provide simplified and more efiiclent apparatus.

0f the drawings, Figures 1, 2 and'3 are diagrammatic illustrations of the inventlon, Figs. 1 and 2 being modifications.

In Fig. 1 an inductance coil ,or receivingcoil 1 is connected between ground G and aerial or antenna A.

A second or potential-raising coil 2 has connected to one of its ends the receiving apparatus comprising detector D, telephone R and battery B. The other end of this coil 2 is free, i. e., not connected to any circuit.

A third coil3 may have one terminal connected to ground at b, as shown, the other terminal being left free. I have found that better results are accomplished by thus dispensing with the closed or secondary circuit heretofore employed.

Each of coils 1 and 3 is adjustable with respect to and inside of fixed coil 2, as indicated by the two double arrows.

The coil or winding 1 is preferably smaller in diameter than coil 2, and may slide inside the latter to vary the coupling between these coils 1 and 2. If coil 2 is (as it ,may be) four and one-half inches in diameter, coil 1 is preferably about three inches in diameter. This provides a very of coils 1, 2 and3.

waves of difierent lengths as indicated by the arrow, being that of any-ordinary antenna coil as used'heretofore.

Coil 2 is a long winding of fine wire, and has a high inductance (19,500 microhenries is suitable).

The third coil 8 is preferably constructed of a fewturns of large or fiat wire, so that its natural period will be high, corresponding to an extremely short wave length. in proportion as this coil might consist of fine wire of many turns, it would absorb energy by coming in tune with the antenna circuit at some particular length of transmltted waves. This coil 3 is preferably only sufliciently smaller in diameter than coil 2' to permit it to slide inside coil 2, but so that the two coils may be brought very close together.

In use, the operator adjusts the relations and the detector D and potentiometer R, B until he obtains the best results, as indicated by telephone T, from any given transmission. No adjustment of the inductances of coils 2 and 3 is needed.

If desired, the relation between coils 2 and 3 may be varied widely wlthout any vanation of the relations between coils 2 and 1, but the latter may be varied also if de- T and potentiometer consisting of resistance sired, or 1 may be varied without varying the relation between coils 2 and 3.

The detector D is preferably of a type having high resistance and best operated by current of high potential, and connected as it is to one end of coil 2, is subjected to the large potential changers thereat. The detector may be any of the so-called crystal rectifiers, particularly those of higher resistance, such as my silicon detector; or may be of the well known gas-rectifier type.

The proper end of the coil 2 nection of the detector depends on various conditions, including the direction of winding of coil 2 relative to coil 1, the form of coil 2, its degree of proximity to coil 1 or other conductors, etc. As there are only two 1 In Fig. 2, the antenna circuit A, t, is like the antenna circuit A, 1, G of Fig. 1.

for the 0011- I ()pen circuited coils 5 and 6 are disposed on opposite sides or ends of antenna coil 4. But coils 5 and 6 are connected together, and are wound in such directions that their outside ends are of opposite potentials, as indicated by the plus and minus signs. Coils 5 and 6 are connected together through detector D, around which telephone T is connected. The coupling between each of coils 5 and 6 with coil 4, may be varied, as indicated by the double arrows; and both couplings may be varied simultaneously.

In Fig. 3, the parts 9, 10, D and T, and the variable couplings indicated by the double arrows, are the same as in Fig. 2, but coils 9 and 10 have a direction of winding which makes their outside ends of the same instead of opposite potentials, as indicated by the plus signs by way of example. The antenna-ground circuit AG has two branches, each containing an adjustable condenser K or K and a coil 7 or 8. The variable coupling of coil 9 is with coil 7, and that of coil 10 is with coil 8. This modification is an embodiment of the form of Fig. 2, modified to adapt it for combination with an intreference preventer which is of the ordinary form so far as concerns the antenna branch circuits. Thus, by detuning one antenna branch, say, A, K, 7 G signals from distant stations will not have effect on coil 9, but full etl'ect on coil 8. Any aperiodic impulse will divide substantially equally in the two branches of the antenna circuit, and will therefore cancel out so far as detector D is concerned, on account of the opposition of coils 9 and 10.

I claim 1. In a radio receiving system, the combination with a receiving coil, of a separate and second coil cooperatively associated therewith and having one end free and a detector-indicator circuit unilaterally connected to one of its ends, and a separate and third coil cooperatively associated with the second coil and having oneend free and the other end connected to earth, substantially as and for the purpose described, substan' tially as. and for the purpose desired.

2. In a radio receiving system, the combination with a receiving coil, of two opencircuited coils arranged cooperatively to each other and to the receiving coil, a detector connected to anopen-circuited coil and a cooperating indicator.

GREENLEAF WHITTIER PIOKARD.

In presence of J. ALBERT PROGTOR, M. C. HANNON. 

